Mobile ditching machine



April 25, 1961 H. 1 MEYER MOBILE DITCHING MACHINE l1 Sheets-Sheet 1 Filed May 28. 1959 1 N .....lwiLrlil n'rromeys April 25, 1961 H. L. MEYER 2,981,012

MOBILE DITCHING MACHINE Filed May 28, 1959 11 Sheets-Sheet 2 INVENTOR.

HENRY L. MEYER HTToR/vsys April 25, 1961 H. l.. MEYER MOBILE DITCHING MACHINE ll Sheets-Sheet 3 Filed May 28, 1959 JNVENTOR. HENRY L. MEYER SN wm.

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EN NNN www Filed May 28, 1959 1l Sheets-Sheet 4 JNVENToR. HENRY L. Maven HTTORNEYs April 25, 1961 H. L. MEYER 2,981,012

MOBILE DITCHING MACHINE Filed May 28, 1959 11 Sheets-Sheet 5 INVENTOR. HENRY L. MEYER HTToRNEys 11 Sheets-Sheet 6 Filed May 28, 1959 com WON

, 1961 H. L. MEYER MOBILE DITCHING MACHINE April 25 ll Sheets-Sheet 7 Filed May 28, 1959 INVENTOR. HENRY L. MEYER flle/auml n-r-roRNsys April 25, 1961 H. L. MEYER 2,981,012

MOBILE DITCHING MACHINE Filed May 28, 1959 11 Sheets-Sheet 8 JNVENToR.

HENRY L. MaveR I April 25, 1961 H.v L. MEYER 2,981,012

MQBILE DITCHING MACHINE med May 2e, 1959 11 sheets-sheet 9 JNVENTOR. HENRY L. MEYER Tanz.' www l MfS q( h4?? HTTORNEYS April 25, 1961 H. L. MEYER 2,981,012

MOBILE DITCHING MACHINE Filed May 28, 1959 ll Sheets-Sheet 10 INPUT OUTPUT IN V EN TOR.

HENRY L. .Maven BY April 25, 1961 H. L. MEYER MOBILE DITCHING MACHINE ll Sheets-Sheet ll Filed May 28, 1959 JNVENToR. HENRY L. MEYER l/Ler Amm/yes 7C @6l HTTo NEyS 2,981,012 Patented Apr. 25, 1961 MUERE DITCHING MACHINE Henry L. Meyer, 'Cleveland Heights, The Cleveland Trencher Company, corporation of Ohio Filed May 28, 1959, Ser. No. 816,436

9 Claims. (Cl. 37--86) Ohio, assigner to Cleveland, Ohio, a

This invention relates to a hydraulically-mechanically controlled and dr1ven digger or ditching machine, and

more particularly is concerned with the provision of a generally propelled in its forward movement and rearward movement through a geared the main power plant, Ito thus lprovide la multiple speed machine. The latter arrangement has not been entirely satisfactory since the most efficient forward Speed of the machine with respect to the speed of the digging unit of tihe machine, during digging operations, is not always attainable, since the various relatively xed forward speeds of the machine may not optimumly match the speed requirements of the soil and the relatively fixed speeds of the digging unit of the machine.

The present invention provides a hydraulically-mechanlcally actuated digger comprising a relatively compact self-propelled vehicle including a retractable and extendable boo-m on which is mounted an endless digging bucket line for excavating the soil in the forward movement of the machine to dig a trench, and which discharges the dug material to a side of the trench. The digger machine of the instant invention includes an improved construction of digging unit or digging bucket line. A novel hytransmission driven by draulic-mechanical drive system is also provided for efciently and effectively propelling the machine proper. The latter is accomplished by means of an engine driven geared transmission drive arrangement for use primarily during roading or manuvering operations, and an engine driven variable volume hydraulic pump-hydraulic motorgeared transmission drive arrangement for use primarily during ditching operations, to provide during the latter operations, infinite possible variations of the forward or feeding speed of the machine in a predetermined range, and wherein the fee-ding or forward speed of the machine may be controlled completely independently of the digging unit or bucket line speed, Ithe latter being driven and controlled directly by the main power plant or engine of the machine. The invention also provides Various other improvements and features in and for a digger of the above mentioned type for increasing the eflciency and usability of the mechanism.

Accordingly, an object of the invention is to provide i an improved digger machine of the type particularly adapted for use in the excavation of utility service line trenches.

Another object of the invention is to provide a hydraulically-mechanically controlled and operated digger machine embodying an engine driven, geared transmission arrangement including a geared auxiliary section, for propelling the machine proper during roading operations and the like, and also embodying a variable output pumphydraulic motor-geared transmission drive arrangement for propelling the machine during digging operations, whereby the feeding speed of the machine during digging operations may be readily changed over innite possible variations within -a predetermined range and wherein the feeding speed may be controlled completely independently of the bucket line speed, such bucket line being mounted on a movable boom.

A further object of the invention is to provide a self propelled digger machine of the above mentioned type which is compact and relatively light-weight in construction which may be eiiiciently operated and controlled by a relatively unskilled operator, with the controls for propelling the machine, for actuating the bucket line, and for raising and lowering the boom, being located in a relatively concentrated area on the machine for optimum actuation thereof by the machine operator.

Other features and advantages of the invention will be apparent from the consideration of the following descn'ption taken in conjunction with the accompanying drawings wherein:

Fig. l is a side elevational view of one side of a digger machine constructed in accordance with the instant invention with the movable boom supporting the bucket line being shown in full lines in digging position, and with the raised position of the digging boom shown in dotted lines.

Fig. 2 is a side elevational view taken from the oppostte side of the machine illustrated in Fig. l, and in particular showing the structure including the bucket cleaner for discharge of the dug material from the bucket line to one side of the excavation.

Fig. 3 is a more or less diagram-matic top plan View showing various hydraulic-mechanical drive elements and connections between the main power plant of the machine and the geared transmission mechanism, and the digging bucket line.

Fig. 4 is a more or less diagrammatic' side elevational view of the arrangement shown in Fig. 3.

Fig. 5 is a generally enlarged, perspective view of one of the buckets and associated chain links of the bucket line.

Fig. 6 is a generally enlarged, partially broken, rear end elevational view of the main and auxiliary sections of the transmission of the digger machine for propelling the same, and as taken from the right hand end of Fig. l, with the bottom portion of the main section being removed to illustrate the lauxiliary section gearing for the hydraulic-mechanical drive of the machine; on the lefthand side of Fig. 6 the manually operated clutch sprocket assembly for selectively connecting the main power plant to the bucket line is illustrated.

Fig. 7 is a sectional plan View of the auxiliary transmission section taken generally along line 7-7 of Fig. 6.

Fig. 8 is a vertical sectional view taken substantially along line 8-8 of Fig. 7.

Fig. 9 is a vertical sectional view of the auxiliary transmission seotion taken substantially along line 9 9 of Fig. 6.

Fig. 10 is an enlarged, sectional view of the sprocket and aforementioned associated manual clutch arrangement for selectively connecting the bucket line to the main power plant of the machine and is taken substantially along the plane of line lid-it) of Fig. 3.

Fig. l1 is a generally diagrammatic lay out of the hydraulic system, including the hydraulic drive components and the associated valve control mechanism, for operating the digger machine `of the invention.

Fig. 12 is a generally diagrammatic, enlarged crosssectional view of the speed control valve illustrated in the hydraulic system of Fig. 11.

Fig. 13 is a vertical sectional end view of the adjustable valve member of Fig. l2 taken generally along line 13-13 of Fig. 12.

Fig. 14 is an enlarged, generally diagrammatic partially broken view of the variable volume wobble plate plunger type pump utilized in the hydraulic system to provide the infinite variations in forward feeding speeds for the digger, and without any waste lluid or heat problems.

Fig. 15 is an enlarged, front elevational view of the yoke element for pivotally mounting the front differential and associated wheel and axle assembly of the digger machine to the machine frame, to thereby insure that all four wheels of the machine are substantially always on the ground and thus minimize ground irregularities.

Fig. 16 is an enlarged, fragmentary, side elevational view of the manually operated cam arrangement for locking the boom and associated `digging unit or bucket line of the digger machine in predetermined position with respect to the adjustable yoke structure `of the excavating unit.

Fig. 17 is an end elevational, partially broken view of the Fig. 16 arrangement, taken generally from the left hand end of Fig. 16.

Fig. 18 is an enlarged, fragmentary end elevational view of the bucket cleaner utilized at the upper end of the bucket line of the instant arrangement, and as taken substantially from the left hand end of Fig. 2.

Referring again to the drawings, the invention is illustrated as being applied to a wheeled, rubber tired vehicle. Such a vehicle comprises a main frame structure supported on traction means consisting, in the embodiment shown, of Iwheel and axle assemblies 12. A main power plant or internal combustion engine 14 is mounted on the forward end of the vehicle, and movable excavating unit structure 16 is pivotally mounted as at 16a adjacent the rearward end of the frame 10. A digger unit or bucket line structure 17, of the ladder-type, is operatively mounted on structure 16 and is arranged to be selectively positioned for the excavation of trenches of various depths, or to be raised out of the ground to an idle position (as shown in dot-dash lines in Fig. 1), generally above the frame 10, during transportation of the machine from place to place. Speed change, geared transmission mechanism generally indicated at 18 with its associated shift lever 13a is mounted on frame 10 intermediate the power unit 14 and excavating unit 17, and serves to transmit power from the main power plant to the main drive shaft 19, which is connected to front and rear differential units 20 and 22 respectively (Figs. 3 and 4) for propelling the machine proper, as will be hereinafter described in detail. The excavating unit 17 is connected, as for instance, by a series of chains and sprockets hereinafter to be more fully described, to the main power plant 14 for driving of the excavating unit.

The digger machine may be provided with dozer blade structure 24 at its forward end with such dozer blade structure being pivotally mounted to frame 10 as at 24a for vertical movement in a generally vertical plane. A reciprocal type double acting, uid powered motor unit 26 pivoted at one end as at 26a tothe frame structure 10 and at the other end as at 26b to the dozer blade structure 24 is also provided for actuation of the latter. The disposition of the dozer blade motor unit 26 and associated control valve mechanism therefore, in the hydraulic system of the digger and for actuating the dozer blade is best seen from Fig. 11 of the drawings and will hereinafter be discussed in greater detail. Pivotal mountings 28 (Fig. 1) are also preferably provided on dozer blade structure 24 for attachment of a towing tongue or bar element '30, shown in phantom lines in Fig. 1, for providing a convenient arrangement for towing the digger machine from place to place. During the latter towing operation, the front wheels will be raised off the ground and the towing bar will be disposed in la generally horizontal position for convenient attachment to a truck or the like. A manually operated, positive clutch element 32 (Fig. 4) operative between the main drive shaft 19 and the rear differential unit 22 is provided for disconnecting the drive shaft from the rear differential during such towing operations. A handle lever 32a (Fig. 4) is provided for actuating clutch 32.

The bucket line 17 is extendably and retractably mounted at the rear end of the machine by means of yoke 35 and associated adjustable length boom structure 37. Yoke 35 comprises a pair of transversely spaced arms 36 pivotally mounted at 16a to the frame 10 and interconnected intermediate their ends by suitable cross-members. Yoke 35 is adapted for movement in a generally vertical plane, and is actuated in such movement by a fluid powered, reciprocal double acting motor unit 33, pivotally connected at one end, as at 33a to frame 10 and pivotally connected at the other end thereof, las at 33b to a bracket 33C attached to one of the arms 36 of the yoke. Boom structure 37 is pivotally mounted on a cross-shaft 38 extending between the arms 36 of the yoke and includes a pair of vertically spaced rotatable members 39 and 40, about which the endless excavating chain or bucket line 17 is looped. 'Ihe chain 42 of the bucket line is provided with a series of excavating buckets 44 which will be hereinafter fully described.

The boom structure 37 of the excavating unit includes a main section 45 of generally elongated box-like oonstruction. The chain 42 at its upper end is looped about aforementioned rotatable member 39 which is in the form of a sprocket secured to shaft 38, and at its lower end about wheel member 40 which is secured to post portion 46 of boom structure 37 and which is adjustably mounted with respect to main section 45 by means of bolt and nut assemblies 48. The aforedescribed construction of the boom structure 37 may be of the general type shown in United States Patent No. 2,648,145, issued August 11, 1953, to Albert R. Askue, and accordingly it is not believed necessary to describe the same in greater detail here. A discharge chute 50 (Fig. 2) is provided on the upper end of the digging unit for discharging the dirt dug by buckets 44, to one side of the excavation, and a crumbing shoe structure 52 of more or less conventional type, having an adjustable foot portion 52a, may be provided for shoving the material inadvertently falling into the trench back into the path of travel of the buckets, to maintain the bottom of the trench comparatively clean and in a manner well known in the art.

An adjustable supporting strut 54 is pivotally mounted to the yoke 35, as at 54a adjacent the innerside of each of -arms 36 of the yoke structure, and comprises an elongated bar-like member having a lengthwise extending slot 56 therein. Struts 54 are disposed in generally juxtaposed relation with main section 45 of the boom 37, and a bolt or threaded projection 57 jutting from each side of the boom section 45 extends through Ithe associated slot in the adjacent strut as may be best seen in Fig. 17. A cam element 58 is pivotally mounted on one end of bolt 57, as at 57a outwardly of the associated slot, and is adapted to engage a washer or platelike element 60 loosely supported on the bolt to force the washer into frictional holding engagement with the strut while drawing up on the bolt element to clamp the boom between the struts 54 and thereby lock the digging element in predetermined position. The other end of bolt 57 is provided with a nut 57b to adjust the locking coacting of the cam. Cam element 58 is controlled by means of linkage and lever structure generally referred to by number 62 land a control lever 62a is provided for actuating such lever and linkage structure, to thereby move the cam element from locking to unlocking positions and vice versa. 4In other words, upon pushing of lever 62a inwardly from the locking position illustrated in Fig. 17, the cam 58 is pivoted out of forced engagement with the washer 60, to permit t unclamping ofthe boom. The lever 62a is readily accessible to the operators station 59, as may be best seen from Fig. 2.

The excavating chain 4t2, in the embodiment illustrated, comprises a plurality of links 62 and 62a (Fig. 5) pivotally interconnected as at 64. Alternate links 62 have a flat plate 66 or 66u secured thereto by any suitable means, such -as welds. Pairs of plates 66, 66a on the stretches of the chain between the two supporting rotatable members 39 `and dit form a substantially continuous surface for providing the back wall 4for the associated buckets Id4. Each plate 66, 66a is provided with an opening 67 which las the links 62, 62a pass sprocket wheel 39, is substantially in line with the too-th or lugs on the upper sprocket wheel 39. rIhus any accumulation of excavated material in the links may be forced outwardly through such openings by the sprocket wheel. Every other plate, or in other words every plate 66, in the embodiment illustrated, carries one of the aforementioned excavator buckets, Iand in this connection each plate 66 is provided with `an outwardly projecting web 63 disposed on .one side of the Iassociated plate and connected thereto by any suitable means such as welds, with the webs 66 being parallel with the chain and extending outwardly at right angles fto the surface of the associated plates. Each web extends rearwardly to substantially the rearward extremity of the next adjacent plate 66a but is not connected thereto and carries on its outer edge 69 a plate 7d of substantially the same width as the plates 66, 66a. These plates 70 extend rearwardly and curve inwardly as at 76a terminating relatively close to the far end of the associated plate 66u. Accordingly, the plates 7! form the front or spade portions of the excavating buckets d4.' The back of the buckets are formed by the paired plates 66, 66a of the respective chain links `and the closed sideof the buckets are formed by the webs 63. Such bucket construction provides for a highly effective digging arrangement in that obstruction of the buckets relatively infrequently occurs and seldom does anything, such as rocks and the like, become wedged in the open sided buckets. Each of the spade plate bucket portions 7d is provided on its outer end with a rooter tip element 72. which is suitably attached to the plate, such as by means of bolts 72a.

In order to provide for closure of the open side of the buckets during the digging operation, to aid in preventing the dug material from being discharged therefrom during upward movement of the bucket line, an elongated channel shaped trough 73 (Fig. l) is carried by the main ,l

section 45 of boom 37. rlhe trough extends vertically from a horizontal plane intermediate the chain supporting members 39 and 4t) to about the axis of rotation of the upper sprocket 39. A trough-like structure '73a is yalso provided on the other or outer side of the excavating unit for guiding the respective stretch of bucket line during its downward movement.

A bucket cleaner 74 (Figs. 2 and 18) is mounted on the upper end of the digging unit, such cleaner comprising a plate element 76 extending into the associated bucket. The element 76 is pivoted to a shank 7S extending downwardly from support structure 78a on the top of the excavating unit and is prevented from rotation on shank 78 by shear pins I82. If there is -an obstruction in the bucket, which might cause breakage or deformation of the bucket cleaner, the shear pins will fracture, thereby permit-ting the bucket cleaner to pivot out of the bucket without damage to the mechanism. As the buckets pass around the sprocket wheel, the rear most edge of the leading plate 66 of each bucket back thereof is separated from the adjacent plate 66a thus opening the bucket -as may be best seen in Fig. 2, and while the buckets are so opened, the aforementioned bucket cleaner or scraper 74 removes any material tending to adhere to the surfaces of the bucket, after which the material is discharged from the bucket and falls through chute to the side of the excavation.

The arrangement for driving the bucket line 17 will now be described. Secured to the raforementioned shaft 38 adjacent one end thereof is a sprocket Wheel 84 (Fig. l) for driving the shaft, and thereby driving the upper chain supporting driving sprocket member 39 of the digging unit. Sprocket 34 is connected as by means of endless link chain 86 to lsprocket 'assembly 86a mounted on counter shaft 87 rotatably supported on the frame 1d, and another endless ilexible chain `87a connects sprocket assembly `86u to a clutch sprocket assembly 8S mounted on inlet shaft 9@ of the auxiliary or coupling section 92 of the transmission i8.

Referring now in particular to Figs. l, 3, 6 and 10 of the drawings, it will be seen that clutch sprocket assembly SS comprises an outer sprocket member 93 (Figs. 3, 6 `and l0) secured to shaft 99 of the lauxiliary section 92 of the transmission l, and an inner sprocket member 93a rotatably mounted on shaft 96 adjacent sprocket 93. Sprocket v93 has a spring loaded plunger element 94 mounted for axial movement in a guide passage da in the hub of the sprocket, and with the plunger 9d connected to la handle portion 95 as by means of Vshank portion 95a. An abutment holding flange element 96 is secured to the hub of sprocket 93 to selectively hold the plunger 94 in retracted position in passage 94a, and against the resistance to compression of spring 94h. The inner sprocket 93a has at least one recess 97 (Fig. 6) formed in the hub portion thereof complementally to the plunger $4 of sprocket 93, and is adapted to receive the plunger 9d therein upon release of the handle 95 from holding coaction with ange 96, to selectively connect sprockets 93 and 93a together. Aforementioned chain `37a is looped about sprocket 93a and it will be apparent that upon driving of sprocket 93, if the latter and sprocket 93a are connected by plunger 94;, sprocket 93u will drive chain S741, sprocketassembly 86a, chain 86, sprocket 8d and driving sprocket $9 of the digging unit, to thereby drive the bucket line 17.

Sprocket 93 of clutch sprocket assembly SS is driven, as for instance by ilexible chain 99 which is :looped iabout sprocket lili?, secured to shaft Mila. A manually operable friction clutch 162 (Fig. 3) selectively clutches shaft lillla to power take off or output shaft ldd of the main power unit ld of the digger machine. An engine reduction gear unit lill of conventional type is preferably associated with clutch unit 102 to enable effective use of the drive from the engine.

From the above, it will be seen that the bucket line will be driven by the main power plant 14 at a speed determined by the speed of the engine ld, upon proper actuation of clutch 162 and sprocket clutch assembly S8.

Clutch 162 is actuated by linkage 165 provided with an operating handle lilSa readily accessible to the operators station S9 on the digger machine. Operating handle 165er is also operatively connected as by means of link age i) to the master brake cylinder L06 of the braking system for the vehicle, such braking system being of the conventional automotive type, and thus not being illustrated here. Thus upon movement of the operating lever 105e in a clockwise direction, as viewed in Fig. 2, the clutch 102 is activated to furnish power to the bucket line and the master brake cylinder is deactivated to release the brakes on the vehicle. Upon movement ofthe lever in the opposite or in a counterclockwise direction, the clutch 192 is deactivated, and the master brake cylinder is activated -to apply the brakes on the wheels of the vehicle. The latter provision of a single operating lever for controlling the clutch which provides a power connection to the bucket line and to the transmission mechanism, and the controlling of the master cylinder of the braking system of the vehicle, provides for optimum control of the machine during `digging operations and in an expeditious manner heretofore unknown in the art.

The transmission mechanism i8, which provides for the aforementioned hydraulic-mechanical drive of the vehicle proper will now be described. Referring in particular to Figs. 6, 7, 8 and 9, the aforementioned shaft 90 on which sprocket clutch assembly 88 is mounted, extends into the one side of the auxiliary section 92 of the transmission housing and is rotatable with respect thereto by means of bearing structure 108. A helical gear 110 is secured adjacent the inner end of the shaft 90 and engages another helical gear 112 disposed above gear 110 and secured to a countershaft 114 (Fig. 9) rotatably mounted in bearing structure 116 in the auxiliary section housing. Secured to shaft 114 adjacent the helical gear 112 is another gear 116 which is adapted for engagement by shifting of coupling gear element 118 (Figs. 7 and 8) mounted on splined shaft 120, the latter being rotatably mounted by bearing structure 122, and generally above and transverse to shaft 90. The shifting gear 118 is mounted for axial movement along supporting shaft 120 and is actuated by a fork element 124 coacting with the gear 118 with the fork element being attached to a manually operable axially movable rod 126. Rod 126 has recesses 127 adapted for coaction with spring loaded detent 127a for proper positioning of shift gear 118 into neutral position or one or the other of its operative positions. Rod 126 is connected to an operating lever 128 (Fig. 3) conveniently located to the machine operators station 59. The shaft 120 is connected at one end, as at 130, to the input shaft 132 of the main section 134 of the transmission 18, such main section being of conventional type, well known in the art, and preferably comprising four forward speeds and a reverse speed. A main transmission section known as a Warner T-9 unit has been found suitable for the instant purposes. Transmission section 134 is actuated by the aforementioned hand operated gear shift lever 18a in the conventional manner. It will be seen therefore that upon lengthwise movement of the shifting gear 118 on the splined shaft 120 into engagement with gear 116 on shaft 114, the main transmission section 134 is positively coupled to the main power plant 13 of the machine assuming that friction clutch 102 is in clutching position, with a chain drive (99) `from the main power plant 14 to the inlet of the auxiliary section 92 of the transmission and a right angled drive to the main section 134 of the transmission.

A sprocket assembly 136 (Figs. 3 and 6) is secured to the output shaft 136a of the main section 134 of the transmission, and is connected by endless chain 138 to a sprocket assembly 140 secured to the main drive shaft 19 of the vehicle. The main drive shaft 19 drives the rear wheels of the vehicle through clutch 32, universal joint 142, and rear differential 22, and drives the front wheels of the vehicle through universal joint 144 and front differential 20. The latter driving arrangement is for use during roading and maneuvering of the vehicle, and provides an effective, readily controllable, mechanical drive for propelling the machine.

The hydraulic driving arrangement for use particularly in driving the machine proper during digging operations will now be described. Projecting from the opposite side of the main power plant 14 of the digger machine as that from which the output shaft 104 projects is another output shaft 146 which has a drive pulley 148 secured to the outer end thereof, such pulley being connected, as by means of a drive belt 150 (Fig. 3) to a pulley 152 mounted on the shaft of a variable volume hydraulic pump 154. The pump, diagrammatically shown in Fig. 14, is of the well known plunger type, including a wobble plate 156 for varying the output of the pump and in the conventional rnanner. The output port 158 lof the pump is connected by feed `line 160 (Fig. ll) to the input end 161 of a speed or flow control valve 162.

The ilow control valve 162 is a variable orifice valve, of the well known slotted plug type, and is connected at the outlet end 163 thereof, back to the variable capacity pump 154, by a pilot line 164 (Fig. 11). As the slotted plug member 166 of the valve is rotated towards fully opened position, by turning of the associated handle elev ment 168, the discharge pressure at the outlet end 163 of the valve is sensed through pilot line 164, by a spring loaded plunger 170 in the pump 154, such plunger being connected as at 172 to the wobble plate 156, to automatically control the eccentricity or tilt of the wobble plate, and thereby increase the capacity or volume of fluid discharged by the pump. If the actuating handle 168 of valve 162 is turned to decrease the tlow of fluid through the valve, the plunger 170 and associated spring 170a senses such decreased flow and accordingly decreases the output of the pump by automatically decreasing the tilt of the wobble plate. It will be seen therefore that the actuation of the speed valve 162 is automatically translated into a control signal for automatically coordinating the output of the variable volume pump 154 with the actuation of the speed valve, thereby eliminating any waste fluid and associated heat problems.

The outlet end 163 of valve 162 is connected by feed line 174 (Fig. ll) to the inlet port 176 of a conventional, 3 spool distributor or directional control valve 178, which may be of the conventional, open center, parallel circuit type, including a pressure relief section 178:1, well known in the art, for controlling the iiow of pressurized uid to the fluid powered motor units which actuate the various mechanisms of the vehicle.

Referring now to Fig. ll, one of these motor units is the aforementioned reciprocal piston and cylinder unit 26 for controlling the movement of the dozer blade 24 on the front end of the vehicle, and is controlled through distributor ports 180, the associated valve spool therefor, and conventional feed and return lines 182. Another of these motor units is the aforementioned double acting, reciprocal unit 33 for actuating the yoke 35, and is controlled through distributor ports 184, the associated valve spool, and feed and return lines 186.

Another of the motor units controlled by distributor valve 178 is a conventional rotary type, hydraulic motor 18S which furnishes the hydraulic driving of the vehicle proper for use during digging operations, to thereby provide infinite possible variations of the forward or feeding speed of the vehicle in a predetermined range, and which may be ycontrolled completely independently of the speed of the mechanical drive actuating the bucket line. Motor 188 is preferably of the reversible type.

The hydraulic motor 188 is controlled through distributor ports 190, the associated valve spool of the distributor valve, and feed and return lines 192, and the rotary shaft 194 of the motor has a driving member, such as sprocket or pulley 196 secured to the outer end thereof (Fig. 3). An endless chain or belt 198 is looped about drive member 196 and looped about sprocket 200 (Figs. 3 and 6) associated with the auxiliary section 92 of transmission 18. Sprocket 200 is secured to an input shaft 202 rotatably mounted with respect to the auxiliary section 92 housing, by means of bearings 204, and at its inner end mounts a worm gear 206 thereon in secured relation.

Referring now to Fig. 7, a worm gear 208 disposed above worm gear 206 coacts with the latter gear 206 and is secured to a shaft 210 extending transverse to shaft 202. Shaft 210 is rotably mounted as by means of bearings 212, and at one end thereof mounts a gear 214 in fixed relation therewith. The aforementioned shifting gear 118 is adapted to be moved into meshing relation with gear 214, upon proper actuation of control handle 123, to thereby drive shaft 120, and input shaft 132 of the main section 134 of the transmission. The main transmission section then drives the main drive shaft 19 of the vehicle in a similar manner as aforedescribed for the mechanical driving arrangement, and through sprocket 136, chain 138 and sprocket to the main drive shaft.

Thus it will be seen that the vehicle feeding or forward speed is precisely controlled by the hydraulic motor 188, which provides infinite possible variations thereof in pre- 9 determined ranges, determined by the gearing in the transmission 18, and completely independently of the mechanical drive to the bucket line, the speed of which is determined by the speed of the main power plant 14 of the vehicle.

The hydraulic motor 18S has a drain line 220 connecting the motor with the reservoir 222 of the hydraulic system, such reservoir preferably embodying a filter 224.

The aforementioned valve spools of the distributor valve 178 are controlled by operating leversV 226, 228 and 230 respectively (Fig. 3) which are conveniently located to the operators station 59. The outlet end 232 (Fig. l1) of the distributor valve is connected back to the reservoir by line 234, and the variable volume pump 154 also has a drain line 236 connecting it to the reservoir and by way of line 234.

In the hydraulic system as shown, a steering pump 23S is provided, connected to the reservoir by feed line 240 and to a power steering motor unit 242, as by feed line 244, for providing power steering for the steering apparatus 245 of the vehicle. Motor unit 242 is drained back to the reservoir by line 246 and by way of line 234. Pump 238 is driven from a pulley 24S mounted on the input shaft of pump 154 and connected to a pulley 250 secured to the input shaft 252 of pump 238 by belt 254 (Fig. 3).

It will be seen therefore that the above discussed hydraulic drive arrangement provides a drive from a variable volume pump to the rotary hydraulic drive motor 18S, the speed of which is controlled by speedvalve 162, with such a system obtaining variation in speed of the drive motor utilizing a variable output pump 154 controlled by the speed valve, and thereby automatically regulating the amount of fluid pumped in coordination with the actuation of thespeed valve, resulting in no waste oil and no heat problem, and contributing to the compactness and simplicity of the vehicle. In a hydraulic drive arrangement which utilized constant displacement pumps, variations in speed would be accomplished by using one or more pumps and by bleeding olf the unwanted pressurized fluid. The energy in the bypassed liuid is converted into heat, which would require a much larger reservoir in the hydraulic system or require some other means for dissipating the heat.

In summary, it will be seen therefore that for road speeds, the mechanical drive for the vehicle is broadly as follows:

Engine 14 to clutch 102, chain drive 99 to right hand inlet (as viewed in Fig. 3) of the auxiliary section a2 of the transmission, right angled gear drive to main section 134 of the transmission, chain drive 138 to main drive shaft 19, and finally universal joint drives 144, 142 to front and rear differentials 2% and 22, and thence to wheel and axle assemblies 12.

For digging speeds for the vehicle, the hydraulic drive -is broadly as follows:

Engine 14 to belt drive 15), to variable volume pump 154, hydraulic lines to speed valve 162, to distributor valve 178, and then to rotary hydraulic motor 188, then chain drive 198 to left hand inlet (as viewed in Fig. 3) of auxiliary section 92 of transmission 1S, right angled gear drive to main section 134 of the transmission, chain drive 138 to main drive shaft 19, and finally universal joint drives 144, 142 to front and rear differentials 2i) and 22, and thence to Wheel and axle assemblies 12.

For controlling the speed `of the bucket line 17 of the digging unit of the vehicle, the mechanical drive is broadly as follows:

Engine 14 to clutch 102 to chain drive 99 to sprocket clutch assembly 88, then chain drive 87a to sprocket assembly 86a on countershaft S7, then chain drive 36 to sprocket 84 to shaft 38 to driver sprocket 39 and thence to bucket line 17.

Referring now to Figs. l and l5, the front wheel and axle assembly is supported on inverted rocker shaped yoke i 10 member 258, which in turn is pivoted as at 260 (Fig. 1) to the underside of frame 10, for pivotal movement in a vertical plane extending transverse of frame 10, to thereby insure that all four wheels of the vehicle are substantial-ly always on the ground, and thus minimize ground irregularities.

The terms and expressions which have been used are used as terms of description and not of limitation and there is no intention in the use of such terms and expressions of excluding any equivalents of any of the features described or shown or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

Iclaim:

l. In a mobile ditching vehicle, a frame, traction mechanism supporting said frame for movement along the ground, an internal combustion main power plant on said frame, a digging unit pivotally mounted on one end of said frame for movement ina generally vertical plane, means for selectively pivoting said digging unit into and out of digging position, means for selectively coupling said` power plant to said dig-ging unit for driving the latter at a speed determined by the speed of said power plant, geared transmission means including a multiple speed main section and an auxiliary coupling section supported on said frame, means for selectively changing the speed gear ratio of said main section, said auxiliary section comprising a shiftable coupling element operatively connected to said main section for actuation of the latter, means connecting said main section to said traction mechanism for driving the latter, means coacting between said power plant and said auxiliary section for selectively coupling said power plant to said element for driving of -the latter and thus actuating said main section, a iluid powered motor unit, a variable volume source of pressurized fluid, valve means for controlling the volume of fluid applied to said motor unit to thereby selectively control the speed of said motor unit, means for translating the actuation of said valve means into a corresponding 'control signal for automatically adjusting the output of said source in coordination with the actuation of said valve means so that no waste pressurized fluid is produced by said source, and means coacting between said motor unit and said auxiliary section for selectively coupling said motor unit to said element when the latter is shifted out of coupled relation with said power plant.

2. In a mobile ditching vehicle in accordance with claim l, including hydraulic brake mechanism for braking the traction mechanism of the vehicle and including a master brake cylinder, the second mentioned means including a power take-off shaft on said power plant, and a manually operable clutch to detachably connect said power plant to said digging unit and to said traction mechanism, a manually operable control lever pivotally mounted on said vehicle, linkage means connecting said lever to said master brake cylinder for controlling the latter, other linkage means connecting said lever to said clutch for controlling the latter, movement of said lever in one direction being operable to activate'said clutch and deactivate said master brake cylinder, movement of said lever in the opposite direction being operable' to deactivate said clutch and activate said master brake cylinder.

3. In a mobile ditching vehicle for service line excavation and the like, a frame, traction mechanism supporting said frame for movement along the ground, said mechanism comprising front and rear wheel and axle assemblies together with front and rear differential units, an internal combustion engine mounted at one end of said frame, a digging unit of the ladder type pivotally mounted on the other end of said frame for movement in a generally Ivertical plane, means including a reciprocal, double acting, `iiuid powered piston and cylinder unit for selectively pivoting said digging unit into and out of digging position, means coacting between said engine and said digging unit for selectively driving the latter, with the speed of said digging unit being controlled by the speed of said engine, geared transmission means including a multiple speed main section having a plurality of forward speeds and at least one reverse speed, and an auxiliary coupling section, supported on said frame intermediate said engine and said digging unit, means for selectively changing the speed gear ratio of said main section, said auxiliary section comprising a shiftable coupling gear operatively connected to the input end of the gearing of said main section for actuation of the latter, a main drive shaft connected to said front and rear differential units through front and rear universal joint mechanism, an endless chain and sprocket assembly connecting the output end of said main section to said drive shaft for rotation of the latter, means coacting between said engine and said auxiliary section for selectively coupling said engine to said coupling gear and thus driving the latter, thereby driving said wheel and axle assemblies through said main section, said chain and sprocket assembly and said drive shaft, a variable output volume pump supported on said frame and being drivingly connected to said engine, a variable orice speed control valve connected to the output port of said pump, a directional control valve connected to the outlet end of said speed valve, a iluid powered, reversible rotary motor unit connected to the distribution ports of said directional control valve, the speed of said motor unit being controlled by actuation of said speed control valve and the direction of rotation of said motor unit being controlled by said directional control valve,'means for translating the actuation of said speed valve into a corresponding control signal for automatically adjusting. the output of said pump in coordination with the actuation of said speed valve so that no waste pressurized fluid is produced by said pump, and means coacting between said motor unit and said auxiliary section for selectively coupling said motor unit to said coupling gear when the latter is out of coupled relation with said engine, to thereby drive said Wheel and axle assemblies by said motor unit and through said main section, whereby infinite possible variations in the speed of said vehicle within a predetermined range are provided.

4. In a mobile ditching vehicle in accordance with claim 3 wherein a clutch is interposed on said drive shaft between said chain and sprocket assembly and said rear universal joint mechanism for detachably connecting said transmission means to said rear wheel and axle assembly, and towing means on the front end of said vehicle for lifting said front wheel and axle assembly above ground level, whereby said vehicle can be readily towed from place-to-place upon attachment of said towing means to a towing vehicle.

5. In a mobile ditching machine, a frame, traction mechanism supporting said frame-for movement along the ground, a main power plant mounted on said frame, a machine operators work station on said frame, a yoke pivotally mounted on one end of said frame for movement in a generally vertical plane, said yoke including transversely spaced arm portions, a shaft extending transversely between said arm portions in supported relation thereon, an elongated boom having one end thereof pivotally mounted on said shaft, a bucket line movably supported on said boom, means for selectively coupling said power plant to said bucket line for driving the latter, means for selectively pivoting said yoke and associated boom and bucket line into and out of digging position, strut means pivotally mounted on said yoke and extending outwardly into juxtaposed relation with said boom, said strut means comprising a transversely spaced pair of elongated members each of which has an elongated lengthwise extending slot therein, projections on said boom extending laterally through the corresponding slot in the respective of said members, means on the outer ends of said projections for releasably clamping said members into tight frictional engagement with the confronting sides of said boom to lock the latter in predetermined position with respect to said yoke and said members, and operating means for actuating said clamping means, said operating means being disposed in accessible relation -to said work station.

6. In a mobile ditching machine in accordance with claim 5 wherein said projections on said boom comprise a bolt extending transversely through said boom and through the adjacent slots in said members, said bolt being threaded on one end and mounting a threaded nut thereon, said nut being operable to coact with the respective of said members to urge the latter into clamping relation with said boom, a cam pivotally mounted on the other end of said bolt and adapted to `be rotated into coacting relation with its respective of said members to urge the latter into clamping relation with the boom while at the same time drawing up on said bolt and associated nut to urge the other of said members into clamping relation with said boom, to thereby detachably lock said boom in predetermined relation with respect to said yoke and said members, said operating means comprising an operating handle movably mounted on said machine, and linkage means connecting said handle to said cam for actuation of the latter.

7. In a mobile ditching vehicle, a frame, traction mechanism supporting said frame for movement along t-he ground, a main power plant mounted on the forward end of said frame, a digging unit mounted on the rearward end of said frame, means for selectively coupling said power plant to said digging unit for driving the same, said digging unit comprising a yoke pivotally mounted on said frame, an elongated boom pivotally mounted at one end to said yoke, a pair of spaced wheels on opposite ends of said boom, at least one of which is provided with sprocket teeth, a bucket-equipped excavator chain ylooped about said wheels and comprising a plurality of pivotally interconnected links, each of said links having an opening therethrough adapted to receive the sprocket teeth for moving said chain with respect to said wheels, a plurality of plates, each of said plates being secured to an alternate link of said chain and extending into overlapping but movable relation with the next adjacent link, said plates coacting with one another to `form a substantially continuous surface on the outer face of straight stretches of said chain to provide bucket ybacks for the buckets of the chain, pairs of said plates providing the bucket back portion for each of the respective buckets, alternate plates having a longitudinally extending generally upstanding plate secured thereto adjacent one side thereof with the last mentioned plate extending from the forward extremity of the respective back plate, rearwardly to substantially the rearward extremity of the adjacent bucket back plate, to form a side wall for each of the buckets, a top plate secured to the respective of each of said side plates and curving inwardly to terminate adjacent said rearward extremity of the respective of said adjacent bucket-'back plates to form the front wall for each of said buckets, a rooter tooth mounted on the leading edge portion of 'each of said top plates, and an elongated trough-like member supported by said boom and extending in the same general direction as said boom, said trough-like member receiving the forward stretch of said chain and associated buckets therein for retaining material dug during exacavating operations, and during upward movement of the chain and buckets with respect to said boom.

8. In a mobile ditching vehicle in accordance with claim 7 wherein a discharge chute is mounted adjacent the upper end of said boom and below the upper extremity of said sprocket wheel, said chute extending 'laterally and downwardly from said upper end of said boom to discharge the material dug by said buckets to one side of the exacavation, and a Ibucket cleaner mounted on said boom above said chute and projecting inwardl1y through the open sides of said buckets into coacting relation with the interiors thereof as the buckets pass around said sprocket wheel, to force dug material sticking to the interiors of said buckets onto said discharge chute.

9. In a hydraulic-mechanical drive system for an excavating vehicle and the like including a main internal combustion power plant having a power take-off shaft ladapted for coupling to an associated digging unit of the vehicle and a geared transmission mechanism, said transmission mechanism comprising a multiple speed main geared section and an auxiliary coupling section, means for selectively changing the speed gear ratio of said main section, said auxiliary section including a shiftable coupling gear operatively connected to the gearing of said main section for actuation of the latter, means coacting between said power plant and said auxiliary section for selectively coupling said power plant to said coupling gear for driving the latter, and thus driving said main section, a variable output volume hydraulic pump, means including a second power take-off shaft on said power plant connecting said pump to said power plant for actuation of said pump, a rotary iluid powered motor unit, means including a variable orice valve connecting said pump to said motor unit to thereby control the speed of '14 f l said motor unit by actuation of said valve, means for translating the actuation of said valve into a corresponding control signal for automatically adjusting the output of said pump in coordination with the actuation of said valve so that no waste pressurized fluid is produced by said pump, and means coacting between said motor unit and said auxiliary section for selectively coupling said motor unit to said coupling gear when the latter is shifted out of coupled relation with said power plant, whereby the speed of said main section may be changed in a predetermined range through infinite possible variations.

References Cited in the levof this patent UNITED STATES PATENTS 1,246,537 Bentson Nov. 13, 1917 1,287,675 Greimann Dec. 17, 1918 1,652,126 Hallar et a1. Dec. 6, 1927 1,762,568 Barber June 10, 1930 2,372,397 Sheroif Mar. 27, 1945 2,648,145 Askue 'L Aug. 11, 1953 2,783,556 Burns et al. Mar. 5, 1957 2,805,079 Vostrez Sept. 3, 1957 2,811,231 McCallum et al. Oct. 29, 1957 '2,923,171 Jedrzykowski Feb. 2, 1960 

